Microsoft® Excel is a spreadsheet system that enables a user to create reports for the manipulation and analysis of data. The Excel container has a number of plugin models. One such model is the Component Object Model (COM) Add-In interface, _IDTExtensibility2. Another is the OLEObject interface. Add-ins are supplemental programs that provide enhanced, optional or customized features. As one example, an appropriate add-in can effectively transform Excel into a frontend for an OLAP (on-line analytical processing) database application. By way of a reporting add-in, the Excel user can query the database server and populate Excel with data returned as the query result. The user can analyze and create reports based on this information. An Excel report of this sort is typically associated with a large quantity of meaningful data and metadata, such as information relating to the queries that have been used in the generation of the report. It is of course highly desirable for such information to be easily and conveniently saved and retrieved by the user. A user can save data in a file separate from the Excel .xls file, but it then becomes difficult to keep the two files consistent, and it cannot be guaranteed that the data will be available whenever the .xls file is available. It is preferable to save such data in the .xls file itself, and to retrieve it in the course of loading the .xls file. It is possible to save data in a hidden sheet in Excel, but the hidden sheet can be made visible and its data tampered with.